The proposal is divided into 7 specific aims. The overall goal of the proposal is to identify the cellular mechanisms that control granulosa cell viability. The investigator has generated preliminary data that both basic fibroblast growth factor, acting through a paracrine or autocrine mechanism and cell contact interact to regulate granulosa cell viability. The cell contact component of this mechanism appears to be mediated via N--cadherin, not by gap junction proteins. Interestingly, the investigators have generated preliminary data which suggests N-cadherin interacts with the receptor for bFGF. This observation suggests that adhesion molecules may modulate cell viability by altering signal transduction through growth factor receptors. This is an interesting general principle in biology which deserves more detailed investigation. As noted above, the proposal is divided into 7 specific aims. In Specific Aim 1, the investigator will determine if a synthetic peptide (LRAHAVDVNG), derived from an amino acid sequence found within the extracellular domains of both the FGF receptor and N-cadherin attenuates bFGF's ability to induce granulosa cell aggregation and maintain granulosa cell viability. In Specific Aim 2, the investigator plans to determine if the N-cadherin antibody prevents bFGF from binding to its receptor. In Specific Aim 3, the investigator will determine if bFGF binds to its receptor and causes the formation of an N-cadherin/FGF receptor complex. In Specific Aim 4, the investigator will determine if N-cadherin antibody attenuates bFGF's ability to stimulate tyrosine phosphorylation of its receptor as well as other proteins. In Specific Aim 5, the investigator will determine if N-cadherin antibody disrupts the actin cytoskeleton of the granulosa cell and thereby induces apoptosis without or prior to altering protein tyrosine phosphorylation. In Specific Aim 6, the investigator will determine if bFGF reduces granulosa cell apoptosis and induces granulosa cell aggregation by regulating the expression of tyrosine phosphorylation status and/or cellular localization of N-cadherin and the associated catenins. In Specific Aim 7, the investigator will determine the protein levels of bFGF, FGF receptor, N-cadherin, and catenins in atretic and non-atretic follicles. The investigator hopes that these studies will provide new insights into the cellular mechanism through which bFGF and granulosa contact interact to regulate granulosa cell viability.